1. Field of the Invention
This invention relates to a closure of the type which may be applied to a helically threaded finish of a glass or rigid plastic container by a press-on action, but which may be normally removed from the finish of the container only by a twisting action. More particularly, this invention relates to a press-on, twist-off closure that is constructed and arranged to optimize torque that is required to remove the closure.
2. Description of the Related Technology
Closure caps of the press-on turn-off variety for glass or hard plastic containers are known and are in wide commercial use. Such closure caps provide a hermetic seal with the container for packing and holding hot-fill or cool food or beverage products such as baby food. Typically, such closure caps have a metallic body including a top panel and a depending skirt portion, both of which are lined with a deformable gasket material. This construction permits the closure caps to be pressed vertically downwardly onto the mouths of glass containers that are provided with circumferential bands of thread formations. The gaskets are formed of suitable plastomeric compounds such as plastisols, which are capable of taking cold flow sets under compression and thereby form thread formations which compliment or mate with those on the neck of the containers. The closure cap may then be removed by a consumer by twisting it like an ordinary twist off closure to unscrew it from the container.
Conventional closure caps of the press-on turn-off variety tend in many cases to be difficult to open for some consumers because of the amount of torque that is required to remove the closure cap from the container. In an attempt to address this issue, certain closure caps that are in commercial use are provided with equally spaced flutes of raised gasket material on the inside of the depending skirt portion of the closure, which is intended to reduce the amount of contact surface between the gasket and the container threads. In actual practice, however, such closures do not always provide the desired removal torque. The inventors have determined that this is due in part to the fact that the equal and symmetrical spacing of the flutes provides too much contact with the embedded glass container threads.
A need exists for an improved closure cap of the press-on turn-off variety that is configurable so as to permit a significant reduction in the amount of torque that is required to remove the closure cap from a container, without compromising the quality of the hermetic seal that is formed with the container during packaging.
Accordingly, it is an object of the invention to provide an improved closure cap of the press-on turn-off variety that is configurable so as to permit a significant reduction in the amount of torque that is required to remove the closure cap from a container, without compromising the quality of the hermetic seal that is formed with the container during packaging.
In order to achieve the above and other objects of the invention, a press-on, twist-off closure for a container of the type that has at least one external thread on a finish portion thereof includes, according to a first aspect of the invention, a panel portion; a skirt portion depending downwardly from the panel portion, the skirt portion and the panel portion together defining a generally cylindrical interior recess; and a deformable gasket mounted within the interior recess, the deformable gasket having a thread engaging portion that is mounted to an inner surface of the skirt portion, and wherein the thread engaging portion comprises a plurality of raised flutes that are integral with the deformable gasket and wherein the raised flutes are arranged in a plurality of separate groups about an inner circumference of the thread engaging portion, each of the separate groups containing at least two flutes, and wherein a circumferential distance between any two adjacent groups is greater than a circumferential distance between any two adjacent flutes within a group, so that when mounted on a container the total span of contact of the flutes across individual external threads of the container will be less than if the flutes were evenly spaced, whereby the torque needed to remove the closure from the container will be less than if the flutes were evenly spaced.
According to a second aspect of the invention, a press-on, twist-off container assembly includes a container having a finish portion with at least one external thread defined thereon; and a press-on, twist-off type closure including a panel portion; a skirt portion depending downwardly from the panel portion, the skirt portion and the panel portion together defining a generally cylindrical interior recess; and a deformable gasket mounted within the interior recess, the deformable gasket having a thread engaging portion that is deformed so as to at least partially conform to the external threads of the finish portion of the container, the thread engaging portion having a plurality of inwardly extending raised flutes, and wherein at least some of the flutes are in contact with at least one of the external threads at respective points of contact, each external thread having a total distance spanned by such points of contact, and wherein an aggregate distance spanned that is a sum of the total distance spanned for all of the external threads is less than an internal circumference of the thread engaging portion.
According to a third aspect of the invention, a press-on, twist-off container assembly includes a container having a finish portion with at least one external thread defined thereon; and a press-on, twist-off type closure including a panel portion; a skirt portion depending downwardly from the panel portion, the skirt portion and the panel portion together defining a generally cylindrical interior recess; and a deformable gasket mounted within the interior recess, the deformable gasket having a thread engaging portion that is deformed so as to at least partially conform to the external threads of the finish portion of the container, the thread engaging portion having a plurality of inwardly extending raised areas, and wherein at least some of the raised areas are in contact with at least one of the external threads at respective lengths of contact, each external thread having a total distance spanned by a sum of such lengths of contact and distances spanned by adjacent raised areas on the thread, and wherein an aggregate distance spanned that is a sum of the total distance spanned for all of the external threads is less than an internal circumference of the thread engaging portion.
According to a fourth aspect of the invention, a press-on, twist-off container assembly includes a container having a finish portion with at least one external thread defined thereon; and a press-on, twist-off type closure including a panel portion; a skirt portion depending downwardly from the panel portion, the skirt portion and the panel portion together defining a generally cylindrical interior recess; and a deformable gasket mounted within the interior recess, the deformable gasket having a thread engaging portion that is deformed so as to at least partially conform to the external threads of the finish portion of the container, the thread engaging portion having a plurality of inwardly extending raised flutes, the flutes being circumferentially spaced irregularly about the thread engaging portion, and wherein at least some of the flutes are in contact with at least one of the external threads at respective points of contact, each external thread having a total distance spanned by such points of contact, whereby the irregular spacing of the flutes will cause the container assembly to have an aggregate distance spanned that is a sum of the total distance spanned for all of the external threads that is less than it would be were the flutes spaced regularly, whereby the amount of torque that is necessary to remove the closure is comparatively reduced.
According to a fifth aspect of the invention, a method of making a press-on, twist-off container assembly includes steps of (a) providing a container having a finish portion with at least one external thread defined thereon; (b) providing a press-on, twist-off type closure including a panel portion and a skirt portion that together define a generally cylindrical interior recess and a deformable gasket mounted within the interior recess that has a thread engaging portion having a plurality of inwardly extending raised flutes; and (c) pressing the closure onto the container so that at least some of the flutes are in contact with at least one of the external threads at respective points of contact, each external thread having a total distance spanned by such points of contact, and wherein an aggregate distance spanned that is a sum of the total distance spanned for all of the external threads is less than an internal circumference of the thread engaging portion.
A method of making a press-on, twist-off container assembly according to a sixth aspect of the invention includes steps of (a) providing a container having a finish portion with at least one external thread defined thereon; (b) providing a press-on, twist-off type closure that includes a panel portion and a skirt portion that together define a generally cylindrical interior recess and a deformable gasket mounted within the interior recess that has a thread engaging portion having a plurality of inwardly extending raised areas; and (c) pressing the closure onto the container so that at least some of the raised areas are in contact with at least one of the external threads at respective lengths of contact, each external thread having a total distance spanned by a sum of such lengths of contact and distances spanned by adjacent raised areas on the thread, and wherein an aggregate distance spanned that is a sum of the total distance spanned for all of the external threads is less than an internal circumference of the thread engaging portion.
A method of making a press-on, twist-off container assembly according to a seventh aspect of the invention includes steps of (a) providing a container having a finish portion with at least one external thread defined thereon; (b) providing a press-on, twist-off type closure that includes a panel portion and a skirt portion that together define a generally cylindrical interior recess and a deformable gasket mounted within the interior recess that has a plurality of inwardly extending raised flutes, the flutes being circumferentially spaced irregularly about the thread engaging portion; and (c) pressing the closure onto the container so that at least some of the flutes are in contact with at least one of the external threads at respective points of contact, each external thread having a total distance spanned by such points of contact, whereby the irregular spacing of the flutes will cause the container assembly to have an aggregate distance spanned that is a sum of the total distance spanned for all of the external threads that is less than it would be were the flutes spaced regularly, whereby the amount of torque that is necessary to remove the closure is comparatively reduced.
These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.